Roamio Plus Out of Home Network Streaming to iPhone not working

I have a Roamio Plus and an iPhone 6s with an updated tivo app
I set up out of home streaming on the app while on my home network
I have a time capsule and airport express on my home network
I can stream on my iPhone while on my home network, but I cannot stream while I am away from my home network.

I am a dumb@$$ when it comes to computers and computer jargon
Can someone give me a step by step fix to this (meaning if you tell me to change something, I need to know how to get to where it is that I need to change whatever it is I'm going to change - get the point?)